Optimized write pole flare angle for side shield or semi side shield PMR writer application

ABSTRACT

Improved writability and a reduction in adjacent track erasure are achieved in a PMR writer with a large flare angle of 45 and 90 degrees in the main write pole and a full side shield or partial side shield configuration around the narrow write pole section and write pole tip. A trailing shield is formed above the write pole&#39;s top surface and a full or partial side shield section is spaced a certain distance from each side of the write pole. The partial side shield has a thickness less than that of the write pole and a top or bottom surface about coplanar with the pole tip&#39;s top or bottom edge, respectively. The partial side shield may include two sections on each side of the write pole wherein the bottom surface of a top section is separated by a certain distance from the top surface of a bottom section.

This is a Divisional application of U.S. patent application Ser. No.11/787,015, filed on Apr. 13, 2007, now U.S Pat. No. 7,872,835,which isherein incorporated by reference in its entirety, and assigned to acommon assignee.

RELATED PATENT APPLICATIONS

This application is related to the following: Ser. No. 11/787,016,filing date Apr. 13, 2007; Ser. No. 11/809,346, filing date May 31,2007; and Ser. No. 12/930,332, filing date Jan. 4, 2011, which areherein incorporated by reference in their entirely and assigned to acommon assignee.

FIELD OF THE INVENTION

The invention relates to a PMR writer having a main pole layer with alarge flare angle and a side shield or semi side shield configurationaround the write pole at the air bearing surface (ABS) plane to improvewritability and cross track field gradient for narrow track widths.

BACKGROUND OF THE INVENTION

Perpendicular magnetic recording (PMR) has been developed in part toachieve higher recording density than is realized with longitudinalmagnetic recording (LMR) devices and is believed to be the successor ofLMR for next generation magnetic data storage products and beyond. Asingle pole writer combined with a soft magnetic underlayer has theintrinsic advantage of delivering higher write field than LMR heads. Aconventional PMR write head as depicted in FIG. 1 typically has a main(write) pole 10 with a small surface area (pole tip) at an air bearingsurface (ABS) 5 and a flux return pole (opposing pole) 8 which ismagnetically coupled to the write pole through a trailing shield 7 andhas a large surface area at the ABS. Magnetic flux in the write polelayer 10 is generated by coils 6 and passes through the pole tip into amagnetic recording media 4 and then back to the write head by enteringthe flux return pole 8. The write pole concentrates magnetic flux sothat the magnetic field at the write pole tip at the ABS is high enoughto switch magnetizations in the recording media 4. A trailing shield isadded to improve the field gradient in the down-track direction.

In FIG. 2, a top view is shown of a typical write pole layer 10otherwise known as the main pole layer or main write pole. The writepole 10 has a narrow section 10 n that extends a neck height (NH)distance from the ABS plane 5-5 to a plane 3-3 parallel to the ABS wherea middle section 10 m having sides 10 s flares out at an angle θ from adashed line 11 that is an extension of one of the sides of narrowsection 10 n. There is also a third main write pole section 10 r thathas one end at the plane 9-9 where the flared sides 10 s terminate andextends a certain distance away from the plane 9-9 in a directionperpendicular to the ABS.

To achieve high areal recording density with PMR technology, keyrequirements for the PMR writer design are to provide large fieldmagnitude and high field gradient in both down-track and cross-trackdirections. In practice, these two requirements are often traded offwith each other to balance the overall performance. There are twoapproaches to achieve these requirements. One approach involvesoptimizing the geometry of the main write pole such as modifying thevalues for NH and flare angle θ. A short NH or large θ can increasewrite field magnitude effectively. However, too short of a NH leads toproblems of meeting process tolerance during manufacturing while toolarge of a flare angle θ may cause a large amount of adjacent trackerasure because of a large fringe field. In today's commercial PMRwriter products, NH is generally above 0.1 micron and flare angle θ iskept less than 45 degrees. A second design approach involves applyingmagnetic shield structure in the vicinity of the main write pole asdescribed by M. Mallary in “One Terabit per Square Inch PerpendicularRecording Conceptual Design”, IEEE, Trans. Magn., Vol. 38, July, 2002.To further improve cross-track field gradient, a full side shield writerstructure is used to limit the excessive fringe field onto the adjacenttrack. Depending on the spacing between the side shield and the writepole, field magnitude could drop below the minimal performancerequirement. As a result, flux intensity will be reduced at the ABS andwritability will decrease.

As recording density keeps increasing, the trade-off between writabilityand field gradient becomes more challenging. Therefore, all the designelements must be integrated and optimized simultaneously to achieve bestperformance. Unfortunately, none of the prior art structures providesatisfactory control of field magnitude and field gradient in both thedown-track and cross-track directions. Therefore, an improved writestructure is necessary to achieve the high performance required foradvanced devices with narrow track widths and high recording density.

Another improvement that is needed with PMR writers is to minimize theamount of pole erasure that occurs when the write pole is comprised ofhigh Bs material. When the current in the coils is turned off, themagnetic field at the write pole tip should ideally be zero to preventunintended writing to the magnetic medium. In actual practice, there maybe a residual field retained at the write pole tip that has a magnitudesufficient enough to cause unwanted writing to the magnetic medium.Current technology has not satisfactorily addressed this concern andbetter PMR write design features are desirable in order to reduce poleerasure.

A search of the prior art revealed the following references. In U.S.Patent Application Publication 2005/0219744, a leading edge taper withan angle of 45 to 50 degrees is formed between a write pole tip and amagnetic flux guide to create sufficient magnetic flux in the writepole. U.S. Patent Application Publication 2006/0044677 describes a writepole layer that has a lower portion with a side that forms an angle of80 to 85 degrees with respect to the bottom edge of the write pole tip.U.S. Pat. No. 6,504,675 describes a PMR writer with a write pole thathas a trapezoidal cross-section at the ABS. To suppress the skew effect,the slope angle of the pole sides may be greater than the maximum skewangle in a drive.

U.S. Pat. No. 6,198,597 discloses a write head in which a rear body of amagnetic pole is connected at an angle of 90 to 120 degrees to the frontbody of the magnetic pole. Opposite end parts on the rear body arecurved to promote convergence of the magnetic fluxes.

U.S. Pat. No. 6,950,277 describes a write pole having a concave shapeddownstream side to optimize field curvature reduction. Adjacent to thewrite pole is a trailing shield with a convex upstream side thatconforms to the curvature in the write pole.

In U.S. Patent Application Publication 2006/0098340, the main magneticpole near the ABS in a PMR recording head is tilted at an angle of 1 to6 degrees relative to a plane that is perpendicular to the ABS andparallel to the plane of the separation layer in order to reducemagnetization inversion noise.

U.S. Patent Application Publication 2006/0092569 describes a magneticstructure having a center rectangular shape with wing portions on twosides near the ABS. This configuration prevents excessive flux fromaccumulating within the structure and thereby prevents stray fieldwriting. In related U.S. Patent Application Publication 2006/0092565,the magnetic structure may be modified to have a central forwardextending portion with first and second laterally extending wings thatcurve away from the ABS to form rounded corners.

U.S. Patent Application Publication 2006/0002019 discloses a PMR writerthat has a bilayer trailing shield gap layer between the main pole andtrailing shield for improving writing and track width control.

SUMMARY OF THE INVENTION

One objective of the present invention is to provide a PMR writerstructure that improves the cross-track field gradient while maintainingsufficient write field magnitude for applications with high recordingdensity and having narrow track widths.

Another objective of the present invention is to provide a PMR writerstructure according to the first objective that minimizes adjacent trackerasure and improves writability at narrow track width.

Still another objective of the present invention is to provide a PMRwriter structure that reduces the amount of pole erasure.

According to the present invention, these objectives are achieved in animproved design of a main write pole layer in combination with a sideshield structure that improves writability and cross-track fieldgradient. The main write pole layer is comprised of a narrow write polesection having one end (pole tip) at the ABS plane and a second endalong a second plane that is parallel to the ABS and located a neckheight distance from the ABS when observed from a top view. There is asecond write pole section with an end that adjoins one end of the narrowwrite pole section at the second plane wherein the second write polesection has a first side that flares outward at an angle θ between 45and 90 degrees from a first side of the narrow section, and a secondside that flares outward at an angle θ from a second side of the narrowsection.

Viewed from the ABS plane, the pole tip has a leading or bottom edge, atop or trailing edge opposite the leading edge, and two sides thatconnect the leading and trailing edges. The top edge may have a greaterwidth than the bottom edge and determines the track width. Adjacent tothe narrow write pole section and a portion of the second section of themain write pole layer is a shield structure including a trailing shieldand a side shield that may have various configurations. The trailingshield may have a rectangular shape with two long sides formed in across-track direction and two short sides perpendicular to the longsides. One long side is a bottom surface of the trailing shield that isformed at a certain distance from the top edge of the pole tip. A firstshort side is formed along a first plane that is parallel to the downtrack direction, and a second side is on a second plane on the oppositeside of the write pole where the second plane is parallel to the firstplane.

In one embodiment, the side shield structure is comprised of a full sideshield having a section along each side of the narrow write pole sectionand pole tip where each section has a top surface, bottom surface, and athickness that is essentially the same as the thickness of the pole tipin a down-track direction. The top surface of the side shield may becoplanar with the top surface of the narrow write pole section orslightly offset below the top surface. Likewise, the bottom surface ofthe side shield may be coplanar with the bottom surface of the narrowwrite pole section or slightly offset above the bottom surface. Eachfull side shield section also has a side essentially parallel to thenearest side of the narrow write pole section and separated from thenearest side by a certain distance (side gap). There is also a side ofthe first full side shield formed along the first plane and a side ofthe second full side shield formed along the second plane.

In a second embodiment, the full side shield design is replaced by apartial side shield having a thickness less the thickness of the poletip and with two sections on opposite sides of the narrow write polesection that are separated from the nearest write pole side by a sidegap distance. A first partial side shield section along one side of thepole tip has a top surface that is coplanar with the top surface of thenarrow write pole section or slightly offset below the top edge and hasa side that is essentially parallel to the nearest side of the narrowwrite pole section. Similarly, the second partial side shield sectionhas a top surface coplanar with the top surface of the first partialside shield section and a side that is parallel to the nearest side ofthe narrow write pole section. There is also a side of the first partialside shield section formed along the first plane and a side of thesecond partial side shield section formed along the second plane.

In a third embodiment, another partial side shield design is disclosedwherein the thickness of the partial side shield is less than thethickness of the pole tip and the partial side shield has two sectionson opposite sides of the narrow write pole section and pole tip that areseparated from the nearest pole tip side by a side gap distance. A firstpartial side shield section along one side of the pole tip has a bottomsurface that is coplanar with the bottom surface of the narrow writepole section or slightly offset above the bottom surface and has a sidethat is essentially parallel to the nearest side of the narrow writepole section. Similarly, the second partial side shield section has abottom surface coplanar with the bottom surface of the first partialside shield section and a side that is parallel to the nearest side ofthe narrow write pole section. There is also a side of the first partialside shield section formed along the first plane and a side of thesecond partial side shield section formed along the second plane.

The present invention also encompasses a fourth embodiment wherein apartial side shield is formed that has two sections on each side of thenarrow write pole section and pole tip. A first section on a first sidehas a top surface coplanar with or slightly offset below the top surfaceof the narrow write pole section and a bottom surface that is parallelto and spaced a certain distance from the top surface of the secondsection on the first side. The second section on the first side has abottom surface that is coplanar with or slightly offset above the bottomsurface of the narrow write pole section. Similarly, there is a firstsection on the second side of the narrow write pole section having a topsurface coplanar with or slightly offset below the top surface of thenarrow write pole section and a bottom surface that is parallel to andspaced a certain distance from the top surface of the second section onthe second side. The second section on the second side has a bottomsurface that is coplanar with or slightly offset above the bottomsurface of the narrow write pole section. Each of the four sections hasone side essentially parallel to the nearest side of the narrow writepole section and a second side formed along either the first or secondplane.

There is a fifth embodiment that is the same as the second embodimentexcept for the addition of a leading shield below the bottom edge of thepole tip and narrow write pole section. The leading shield may have arectangular shape with two longer sides formed parallel to the bottomedge of the write pole tip. In one embodiment, the length of the longsides in the leading shield is equivalent to the length of the longsides in the trailing shield. The long side of the leading shieldnearest the write pole tip is the top surface and is formed a certaindistance from the bottom edge of the write pole tip. One short side ofthe leading shield is formed on the first plane and the other short sideis formed on the second plane.

From a top view, the side shield sections preferably conform to thenarrow write pole section and to a portion of the main pole layer withflared sides adjacent to the narrow write pole section. In other words,each side shield section has a first side that is parallel to the sidesof the narrow write pole section of the main pole layer and a secondside connected to the first side that is parallel to a flared side inthe second section of the main pole layer. A third side is formed alongthe ABS plane and a fourth side of the side shield may be perpendicularto the ABS plane and parallel to the first side and formed along thefirst or second plane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a conventional PMR writer showingthe main write pole, flux return pole, magnetic recording media, andcoils that generate magnetic flux.

FIG. 2 is a top view showing a main write pole layer of a conventionalPMR write head that has a narrow write pole section adjacent to the ABSand a larger section with sides that flare outward at an angle θ fromthe sides of the narrow write pole section.

FIG. 3 is a cross-sectional view from an ABS plane that shows a PMRwrite head structure having a full side shield and a trailing shieldaccording to one embodiment of the present invention.

FIG. 4 is a cross-sectional view from an ABS plane that depicts a PMRwrite head structure with a partial side shield and a trailing shieldaccording to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view from an ABS plane that depicts a PMRwrite head structure with a partial side shield and a trailing shieldaccording to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view from the ABS plane showing a PMR writehead structure having a partial side shield with two sections formed oneach side of the write head according to fourth embodiment of thepresent invention.

FIG. 7 is a cross-sectional view from the ABS plane showing a PMR writehead having a leading shield, trailing shield, and partial side shieldaccording to a fifth embodiment of the present invention.

FIG. 8 is a top view of the PMR write head in FIG. 7 in which thetrailing shield has been removed to show the write pole and partial sideshield.

FIG. 9 is a graph illustrating the perpendicular field vs. distance tothe writer pole center for various conventional PMR write head designsand for a PMR write head formed according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is a PMR writer comprised of a main write polelayer having top and bottom surfaces and two sides and includes a narrowwrite pole section with one end (pole tip) at the ABS and a secondlarger section that has sides which flare outward from the end of thenarrow write pole section opposite the ABS. The PMR writer is alsocomprised of a shield structure with a trailing shield formed above thetop surface of the narrow write pole section and a side shield withvarious configurations disposed on opposite sides of the main write polelayer. The drawings are provided by way of example and are not intendedto limit the scope of the invention. Moreover, the elements in thefigures are not necessarily drawn to scale and may have differentrelative sizes in an actual device.

Referring to FIG. 3, a cross-sectional view is shown from an ABS planethat represents a first embodiment of the present invention. There is amain write pole layer, hereafter referred to as the main write pole,having a surface (pole tip 20 t) at the ABS comprised of a bottom edge20 a, a top edge 20 b, and two sides 20 c, 20 d that is formed on asubstrate 16 that may be a separation layer made of Al₂O₃ between a readhead and a write head in a separated PMR read-write head, for example.However, the PMR writer is not limited to a separated PMR read-writehead and may encompass other PMR writer configurations as appreciated bythose skilled in the art. It should be understood that the main writepole has a bottom surface that terminates in the bottom edge 20 a, and atop surface that terminates in the top edge 20 b at the ABS.Furthermore, the substrate may be part of a slider (not shown) formed inan array of sliders on a wafer. After the PMR write head is completed,the wafer is sliced to form rows of sliders. Each row is typicallylapped to afford an ABS before dicing to fabricate individual slidersthat are used in a magnetic recording device.

From a top view in FIG. 8, the main write pole 20 has a narrow section20 n formed between the ABS plane 27-27 and a parallel plane 32-32 thatare separated by a neck height distance z. There is also a secondsection 20 m whose sides 20 s, 20 r flare outward at an angle θ from theplane 32-32 with respect to dashed lines 33, 34 that are extensions ofthe narrow write pole section sides which are perpendicular to the ABS27-27. The main write pole 20 may be deposited by an electroplatingmethod and may be comprised of a material such as CoNiFe or FeCo thathas a high saturation magnetic flux density (Bs) and a plated thicknessof about 0.7 to 0.9 microns.

Returning to the exemplary embodiment in FIG. 3, the write pole tip 20 thas a top edge 20 b having a width w₁ at the ABS that is also known asthe track width. In addition, there are two sides 20 c, 20 d thatconnect the ends of the top edge 20 b and bottom edge 20 a to form aninverted trapezoidal shape. The track width w₁ of 0.05 to 0.15 micronsis wider than the width of the bottom edge 20 a and is typicallydetermined by an ion milling process that removes excess material fromthe sides of the main write pole layer. A chemical mechanical polish(CMP) step is typically employed to form a smooth pole tip 20 t alongthe ABS plane. The thickness t of the write pole tip 20 t is defined asthe distance between the top edge 20 b and bottom edge 20 a along a linethat is parallel to the y-axis and is about 0.15 to 0.30 microns. Thetop edge 20 b and bottom edge 20 a are part of a top surface and bottomsurface, respectively, of the narrow write pole section and theaforementioned surfaces are oriented perpendicular to the ABS plane.

There is a trailing shield 21 above the write pole tip 20 t that has twolong sides formed parallel to the top edge 20 b and top surface of thenarrow write pole section and with a width w₃ in a cross-track (x-axis)direction. The long side that is closer to the top edge 20 b is thebottom surface of the trailing shield 21 and is separated from the topedge by a distance h that is preferably about 0.03 to 0.10 microns. Inone embodiment, the trailing shield 21 has a rectangular shape and oneshort side 21 s that lies on a plane 30-30 and a second short side 21 sthat lies on a plane 31-31 wherein both of the aforementioned planes areparallel to the y-axis but are positioned on opposite sides of the writepole tip 20 t. The sides of the trailing shield 21 extend a distance ofabout 1 to 10 microns away from the ABS and may partially overlap otherportions of the main write pole (not shown) besides the narrow writepole section.

Furthermore, there is a full side shield having a section 18 on one sideof the write pole tip 20 t and a second section 19 on the opposite sideof the write pole tip wherein the thickness of the sections 18, 19 isessentially equal to thickness t along the ABS plane. In one embodiment,the section 18 has a side 18 s on the plane 31-31 and the section 19 hasa side 19 s on the plane 30-30. The top surfaces of the sections 18, 19may be coplanar with the top edge 20 b and the bottom surfaces of thefull side shield sections may be coplanar with the bottom edge 20 a.Optionally, the top surfaces and bottom surfaces of sections 18, 19 maybe slightly offset by up to about 0.15 microns from the top edge 20 band bottom edge 20 a, respectively, along the down-track axis (y-axis).The top surfaces of sections 18, 19 have a width w₂ and the bottomsurfaces have a width w₄ in the cross-track direction wherein w₂<w_(t).The full side shield sections 18, 19 also have a side that is alignedessentially parallel to the nearest write pole side 20 c, 20 d,respectively, and spaced a distance r of about 0.04 to 0.10 microns fromthe nearest side of the write pole tip 20 t. In one embodiment, the mainwrite pole 20, trailing shield 21, and full side shield sections 18, 19may be made of CoFe, CoFeNi, or NiFe or the like and may be deposited bya well known electroplating method on a seed layer (not shown), forexample.

One fabrication sequence for forming the aforementioned magneticelements is provided in related Headway application HT06-017 which isherein included by reference in its entirety. The gap 40 between thewrite pole tip 20 t and trailing shield 21 may be filled with a writegap (WG) made of Al₂O₃, silicon oxide, or NiCu, for example. The spacein the side gap 37 may be comprised of a trilayer configuration (notshown) having a lower side gap layer, a middle CMP stopper layer, and anupper magnetic seed layer that are deposited by an atomic layerdeposition (ALD) method or the like. Gap 38 between the side shieldsections 18, 19 and the substrate 16 may be comprised of a lower aluminalayer (not shown) formed by a PVD method, for example, and a metal maskmade of Ta, Ru, NiCr, Ti, or the like formed on the lower alumina layer.

Referring to FIG. 4, the present invention also encompasses a secondembodiment in which a partial side shield comprised of a first section23 with a side 23 s on the plane 31-31 and a second section 24 on theopposite side of the write pole tip 20 t wherein the second section hasa side 24 s on the plane 30-30. In one aspect, the two sections 23, 24each have a top and bottom surface, a side along a plane 31-31 or 30-30,and a side that is aligned essentially parallel to the nearest side 20c, 20 d, respectively, and spaced a side gap distance r of about 0.04 to0.10 microns from the nearest side of the write pole tip 20 t. Note thatthe partial side shield has a thickness g in the down-track direction ofabout 0.05 to 0.15 microns which is less than the thickness t of thewrite pole tip 20 t in the down track direction along the ABS planebetween top edge 20 b and bottom edge 20 a. The top surfaces of thesections 23, 24 may be coplanar with the top edge 20 b or the topsurfaces of sections 23, 24 may be offset below the top edge 20 b by adistance between 0 and 0.15 microns along the down-track axis. The topsurfaces of sections 23, 24 have a width w₂ of 0.5 to 30 microns whichis less than the width of the bottom surfaces 23 e, 24 e of the partialside shield sections 23, 24, respectively. The distance p between thebottom surfaces 23 e, 24 e and the bottom edge 20 a in a directionparallel to the y-axis may be smaller or greater than thickness g. Notethat g+p=t. There is also a trailing shield 21 as described earlier thatis formed a distance h above the top edge 20 b of the write pole tip 20t. Side shields 23, 24 are made of the same soft magnetic material suchas CoFe, CoNiFe, or NiFe as in full side shield sections 18, 19.

Referring to FIG. 8, a top view of the main write pole 20 and partialside shield sections 23, 24 along with a larger section 20 m of the mainwrite pole is illustrated. The trailing shield 21 above the pole tip 20t has been removed to simplify the drawing. The narrow section 20 nextends from the pole tip 20 t at the ABS plane 27-27 to the plane 32-32where the larger section 20 m of the main pole layer flares outward atan angle θ with respect to the dashed lines 33, 34 that are extensionsof the pole tip sides 20 c, 20 d, respectively. The distance z betweenthe planes 27-27 and 32-32 is between 0 and about 0.2 microns and isalso referred to as the neck height. The larger section 20 m extends adistance a of about 0.1 to 20 microns away from the plane 32-32 in adirection perpendicular to the plane 32-32. The angle θ is preferablybetween 45 degrees and 90 degrees to help concentrate the magnetic fluxfrom the main write pole at the pole tip 20 t and to counter balance theflux leakage loss to the partial side shield sections 23, 24. Withoutthe shield structure described in the present embodiment or in otherembodiments involving a trailing shield and either a full or partialside shield, the large flare angle θ would cause too much fringe fieldat the adjacent track. It should be understood that the top view of themain write pole 20 as described with respect to FIG. 8 is the same inall embodiments of the present invention.

The process flow during fabrication is simplified by making the partialside shield sections 23, 24 conformal with the flared sides 20 r, 20 sof the main write pole. In other words, partial side shield section 23has a side 23 c that is essentially parallel to a portion of the flaredside 20 s that is adjacent to section 20 n and is separated from theside 20 s by a distance k that may be equal to r. Likewise, partial sideshield section 24 has a side 24 c that is essentially parallel to aportion of the flared side 20 r adjacent to section 20 n and isseparated from the side 20 r by a distance k. Partial side shieldsections 23, 24 also have sides 23 b, 24 b, respectively, that areperpendicular to the ABS plane 27-27 and parallel to the narrow section20 n of the main write pole 20. In addition, there are sides 23 s, 24 sas mentioned previously that are formed along the planes 31-31 and30-30, respectively. In the exemplary embodiment, the length n₁ of thesides 23 b, 24 b is about 0 to 0.2 microns and is less than the distancez of about 0 to 0.2 microns that separates plane 32-32 from the ABSplane 27-27 whereas length n₂ of the sides 23 s, 24 s is greater thanthe neck height distance z. In current commercial PMR writers, the neckheight is typically greater than 0.1 micron and the flare angle θ isbelow 45 degrees.

In FIG. 5, a third embodiment is depicted that also involves a partialside shield configuration in addition to the trailing shield 21described previously. In this case, the two partial side shield sections35, 36 are formed on opposite sides of the write pole tip 20 t andnarrow write pole section. Section 35 has a side 35 s along the plane31-31 and section 36 has a side 36 s along the plane 30-30. In oneaspect, the two sections 35, 36 each have a top and bottom surface, aside along a plane 31-31 or 30-30, and a side that is alignedessentially parallel to the nearest side 20 c, 20 d, respectively, andspaced a side gap distance r of about 0.04 to 0.10 microns from thenearest side of the write pole tip 20 t. Note that the partial sideshield sections 35, 36 have a thickness b in the down-track direction ofabout 0.05 to 0.25 microns which is less than the thickness t of thewrite pole tip 20 t in the down track direction along the ABS plane. Thebottom surfaces 35 e, 36 e of the sections 35, 36, respectively, may becoplanar with the bottom edge 20 a or the bottom surfaces 35 e, 36 e maybe offset by a distance between 0 and 0.15 microns above the bottom edge20 a along the down-track axis. The top surfaces of sections 35, 36 havea width that is less than the width w₄ of the bottom surfaces 35 e, 36e. The distance e between the top surfaces of sections 35, 36 and thebottom surface of trailing shield 21 is greater than h and may be lessthan or greater than thickness b. Gaps 37, 38, 40 were describedpreviously with respect to the first embodiment.

Referring to FIG. 6, a fourth embodiment is shown in which there is atrailing shield 21 and a partial side shield configuration having twosections on each side of the narrow write pole section and write poletip 20 t. In one aspect, there are two sections 18, 35 on one side ofthe pole tip 20 t and two sections 19, 36 formed on the other side ofthe pole tip. The sections 18, 19, 35, 36 were described previously.Note that there is a distance c of from 0.05 to 0.20 microns in they-axis direction between the top surface of section 35 and bottomsurface of section 18 and a similar spacing between the bottom surfaceof section 19 and top surface of section 36. The side gap distance rremains in effect between the pole tip side 20 c and parallel sides ofsections 18, 35, and between the pole tip side 20 d and parallel sidesof sections 19, 36.

Referring to FIG. 7, a fifth embodiment is depicted which is the same asthe second embodiment except that a leading shield 22 is added to theshield structure and replaces substrate 16. The leading shield 22 has athickness f of about 0.2 to 5.0 microns along the ABS plane. In theexemplary embodiment, the leading shield 22 has a rectangular shape withtwo long sides formed parallel to the bottom edge 20 a and having awidth w₃. The long side (top surface) nearest the bottom edge 20 a ispositioned a distance v of about 0.05 to 0.15 microns from the bottomedge 20 a. One short side 22 s lies on the plane 31-31 while the secondshort side 22 s lies on the plane 30-30. This embodiment is similar tothe shield structure disclosed in related Headway application HT06-033,which is herein included by reference in its entirety, except that nomagnetic side connections are present. However, it should be understoodby those skilled in the art, that magnetic connections may be addedbetween two or more magnetic shield elements in all five embodimentsdisclosed herein without departing from the spirit of the invention.Magnetic side connections are added in some cases to ensure a correctmagnetic potential in the shield elements.

One advantage provided by the present invention is shown by a simulationin FIG. 9 where the magnitude of the perpendicular field component (Hy)is plotted as a function of cross track direction or distance to thewrite pole (pole tip) center along the x-axis. The horizontal line 50 inthe plot is the constant H=Hc where Hc is media coercivity. The resultsrepresented by dashed line 51 are for a prior art design where the flareangle in the main write pole is 30 degrees and there is no side shield.Another prior art design demonstrates the effect of increasing the flareangle in the main write pole to 60 degrees when there is no side shield.Note that the thick dashed line 54 shows a higher field magnitude but atthe expense of a much poorer field gradient for the 60 degree flareangle and no side shield example. The line 52 represents a prior artdesign where the flare angle is 30 degrees and a full side shield isadded. The cross-track field gradient is improved compared with line 51but there is an undesirable loss in field magnitude. On the other hand,a combination of large flare angle (θ=60 degrees) and a side shieldstructure according to the present invention generates an improved fieldgradient without compromising the field magnitude as indicated by solidline 53. As a result, a PMR writer that incorporates a shield structureaccording to the present invention will have improved writability andless erasure of adjacent tracks at narrow track width. Another advantageof the composite shield structure represented by embodiments in FIGS.3-7 is that the fabrication process can be accomplished with existingmethods and tools and in a simpler fashion than for the full side shielddesign in the prior art. Furthermore, it is believed that there will beless pole erasure when high Bs materials are used in the write pole tipbecause of the improved shield design disclosed herein.

While this invention has been particularly shown and described withreference to, the preferred embodiment thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade without departing from the spirit and scope of this invention.

1. A PMR write head, comprising: (a) a main write pole having a narrowwrite pole section with a pole tip at an ABS plane, a pole tip thicknessin a down-track direction, two sides formed perpendicular to the ABS, atop surface with a top edge at the pole tip, and a bottom surface with abottom edge at the pole tip, and a second section formed a certaindistance from the ABS wherein the second section has two sides thatflare out at a angle θ from the two sides of the narrow section at anend opposite the ABS, said end is a neck height distance from the ABS;and (b) a shield structure comprised of: (1) a trailing shield having abottom surface formed a certain distance above said top surface of thenarrow write pole section and separated therefrom by a gap layer, andtwo sides at the ABS that are parallel to the down track direction andformed along first and second planes, respectively; and (2) a sideshield having a section formed on each side of the narrow write polesection wherein each side shield section has a top surface having awidth at the ABS in a cross-track direction, a bottom surface parallelto the top surface and separated therefrom by a pole tip thickness, aside facing away from the narrow write pole section having a length lessthan the pole tip thickness and formed parallel to the down-trackdirection and along a first or second plane, a side having a length lessthan the neck height that is parallel to the nearest side of the narrowwrite pole section and spaced a side gap distance from said nearestside, and a side that is essentially parallel to the nearest flared sideof the second section.
 2. The PMR write head of claim 1 wherein the sideshield is a partial side shield having a top surface that is aboutcoplanar with the top surface of the narrow write pole section, said topsurface has an offset of 0 to about 0.15 microns below the top edge ofthe pole tip along the down-track axis.
 3. The PMR write head of claim 1wherein the side shield is a partial side shield having a bottom surfacethat is about coplanar with the bottom surface of the narrow write polesection, said bottom surface of the partial side shield has an offset of0 to about 0.15 microns above the bottom edge of the pole tip along thedown-track axis.
 4. The PMR write head of claim 2 wherein the shieldstructure is further comprised of a leading shield formed below thebottom surface of the narrow write pole section and having a top surfaceseparated from the bottom edge of the pole tip, and a first side andsecond side that lie along the first plane and second plane,respectively.
 5. A PMR write head, comprising: (a) a main write polelayer having a narrow write pole section with a pole tip at an ABSplane, a pole tip thickness in a down-track direction, two sides formedperpendicular to the ABS, a top surface with a top edge at the pole tip,and a bottom surface with a bottom edge at the pole tip, and a secondsection formed a certain distance from the ABS wherein the secondsection has two sides that flare out at a angle θ from the two sides ofthe narrow section at an end opposite the ABS; and (b) a shieldstructure comprised of: (1) a trailing shield having a bottom surfaceformed a certain distance above said top surface of the narrow writepole section, and two sides at the ABS that are parallel to the downtrack direction; and (2) a partial side shield having two sectionsformed on each side of the narrow write pole section wherein a topsection on the first and second sides of the narrow write pole sectionhas a top surface having a width at the ABS in a cross-track direction,a bottom surface parallel to the top surface, a side parallel to thedown-track direction, and a side that is parallel to the nearest side ofthe narrow write pole section and spaced a second distance from saidnearest side and wherein a bottom section on the first and second sidesof the narrow write pole region has a bottom surface having a width atthe ABS in a cross-track direction, a top surface parallel to the bottomsurface, and a side parallel to the down-track direction, a sideparallel to the nearest side of the narrow write pole section and spaceda second distance from said nearest side, said bottom surface of a topsection and top surface of an underlying bottom section are separated bya third distance.
 6. The PMR write head of claim 5 wherein a side of thetrailing shield and the sides of the top and bottom sections on one sideof the write pole tip that are parallel to the down track direction areformed along a first plane that is perpendicular to the ABS, and asecond side of the trailing shield and the sides of the top and bottomsections on the opposite side of the write pole tip that are parallel tothe down-track direction are formed along a second plane that isperpendicular to the ABS.
 7. The PMR write head of claim 5 wherein angleθ is between about 45 degrees and 90 degrees.
 8. The PMR write head ofclaim 5 wherein the top surface of the top sections in the partial sideshield lie on a plane that is offset from the top surface of the narrowwrite pole section by a distance of 0 to about 0.15 microns below thetop edge of the pole tip.
 9. The PMR write head of claim 5 wherein thebottom surface of the bottom sections in the partial side shield lie ona plane that is offset from the bottom surface of the narrow write polesection by a distance of 0 to about 0.15 microns above the bottom edgeof the pole tip.
 10. The PMR write head of claim 5 wherein the thirddistance is between about 0.05 and 0.15 microns.
 11. The PMR write headof claim 5 wherein the main write pole layer and shield structure arecomprised of CoFe, CoFeNi, NiFe, or other soft magnetic materials. 12.The PMR write head of claim 5 wherein the distance between the ABS planeand the end of the narrow write pole section opposite the ABS is from 0to about 0.2 microns.
 13. The PMR write head of claim 5 wherein thesecond distance is a side gap distance of about 0.04 to 0.10 microns.